In recent years, multilayer ceramic capacitors have been mounted in various electric devices. Various dielectric materials used for multilayer ceramic capacitors of this type have also been studied and developed actively, and of these dielectric materials, a dielectric ceramic composition containing an alkali metal niobate-based perovskite compound has also been proposed.
For example, PTL 1 proposes a dielectric ceramic composition containing a main compound represented by (KaNabLicM2d)(NbwTaxMgyM4z)O3, wherein M2 is at least one of Ca, Sr, and Ba, and M4 is at least one of Zr, Hf, and Sn, satisfying relationships of w+x+y+z=1, 0.07≤a≤0.92, 0≤b≤0.81, 0≤c≤0.09, 0.57≤a+b+c≤0.95, 0.1≤d≤0.4, 0.95≤a+b+c+d≤1.05, 0.73≤w+x≤0.93, 0≤x/(w+x)≤0.3, 0.02≤y≤0.07, and 0.05≤z≤0.2, and containing 2 to 15 parts by mol of Mn relative to 100 parts by mol of a total content of Nb, Ta, Mg, and M4.
According to PTL 1, a dielectric ceramic composition having the above composition is used to obtain a multilayer ceramic capacitor whose insulation resistance hardly decreases even when firing is performed in a reducing atmosphere and which has a small capacitance-temperature change rate in a wide temperature range, and accordingly has good insulating properties and good dielectric characteristics even when an inexpensive base metal such as Ni is used for internal electrodes.    PTL 1: WO 2014/162752 (claims 1, 2, paragraph [0011])